1. Technical Field
The present invention relates to an optical disc recording /reproducing apparatus and a data recording method for use with such apparatus. More particularly, the present invention relates to an apparatus and method for recording the data on an optical disc, such as CD-R, CD-RW, DVD-R, MO and the like, wherein the data recording can be performed beyond the nominal storage capacity of such optical disc that contains any particular information such as addresses and the like previously written on the wobbles thereof.
2. Prior Art
An optical disc such as a write-once CD-R, rewritable CD-RW and the like contains the embedded information (ATIP information) such as addresses and the like that have previously been written in a particular sequence on the wobbles in accordance with the specifications, and the information that represents the locations (addresses) on the optical disc may be retrieved by reading the embedded information from the disc. The embedded information includes the information items as listed in Table 1, which may be written in the read-in areas and other areas.
TABLE 1M1:S1:F1Content0:0:0time code in read-in area and program area1:0:0time code in read-in area, PCA and PMA1:0:1recording power, reference speed, application code and disctype ID1:1:0read-in area start time1:1:1read-out area start time0:0:1speed range, recording strategy and OPC parameter atreference speed0:1:0recording power and OPC parameter at low & high speeds0:1:1reserved
As shown in Table 1, (1:1:0) and (1:1:1) in the MSB bits, represent the information for the read-in area start time and the information for the read-out area start time, respectively, and the recording can be performed during the period, which is called the recordable time, from the read-in area end time to the read-out area start time. The actual data may be recorded on those areas during the above recordable time. FIG. 6 illustrates the concept of a typical optical disc, such as the musical CD-R disc having its nominal recordable time of 74 minutes, for example. As shown in FIG. 6, the interval between the read-in end position 31a and read-out start position 32 across the tracks on the disc 30 corresponds to at least 74 minutes.
In the regions following the above read-out start position (nominal recordable end position), the read-out information, which indicates the end of the data recording area may be written. In the usual optical disc, however, some free regions may still be available at addresses following the areas in which the read-out information has been written. This means that some recordable regions are available at addresses toward the outer peripheral side of the disc. Some servo errors, such as the focusing error and tracking error, might occur if any recording would be attempted in those recordable regions. In order to ensure that the read-out information can be recorded without causing such servo errors, some margins (free tracks that correspond to several minutes when they are expressed in terms of the time ) may be reserved by considering variances in individual optical discs.
In some recently developed CD-R or CD-RW discs, however, it may be seen from the track structure in FIG. 7 that the information may be written beyond the nominal recordable end position (point A in FIG. 7) and as far as the end of the available tracks (point B in FIG. 7) where errors might occur. Thus, the recording can be performed beyond the nominal recordable time of the optical disc. This is called the “overburn-based recording” technique, which is becoming popular. Using this overburn-based recording technique, music can be recorded for more than 74 minutes on a 74-minute musical CD-R disc, for example.
In the conventional hardware and software that implement the overburn-based recording technique, however, the recording might occur as far as it is permitted, and if any out-of-tracking/out-of-focusing situation should occur during the recording process, the recording would be stopped there. This “at random” approach is the only way to solve the out-of-tracking/out-of-focusing problem.
When the recording was performed on the disc in the above manner, the read-out information might also not have been recorded on the disc properly. This would cause the out-of-tracking/out-of-focusing situation at the end of the tracks where the information has been recorded. Very often, this would cause the problem in that the information could not be reproduced properly. For the musical optical disc that contains the music data, for example, this problem would appear as breaks or interruptions in the music when it is replayed. This problem can be avoided if the user has a prior knowledge of the accurate recordable time or recordable capacity of a particular optical disc, before the user actually begins to record the data on the optical disc.
As an alternative to using the above method, one possible method would be to determine any additional time on an empirical basis that can be extended for the recording, without causing the above problem, and to extend the recordable last position as far as the position obtained by adding the above extended time to the read-out area start time. Although this method may permit the data or music to be recorded on the extended area on the disc, it still has the problem in that the additional time that can be extended must be small in order to ensure that the recording can occur with safety, when it is considered that there are some variances in the individual optical discs. For this reason, the additional time cannot be extended sufficiently. The additional time may be extended at the sacrifice of the recording safety, but if so, the tracking errors or focusing errors as described above would be caused for some types of optical discs.
The present invention addresses the problems described above, and a principal object of the present invention is to provide an optical disc recording/reproducing apparatus and a data recording method for use with such apparatus, wherein the overburn-based recording technique that is implemented by the apparatus and method allows the effective recording time and/or capacity of an optical disc to be extended and/or increased with safety and reliably.